Catalysts containing nano-materials and methods of making and using same

ABSTRACT

A method of making a catalyst containing nanosize zeolite particles supported on a support material is disclosed. A process for making styrene or ethylbenzene by reacting toluene with a C 1  source over a catalyst containing nanosize zeolite particles supported on a support material is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No.12/938,453, filed on Nov. 3, 2010.

FIELD

The present invention is generally related to the production of styreneand ethylbenzene. More, specifically, the embodiments of the presentinvention relate to catalysts for the production of styrene andethylbenzene.

BACKGROUND

Styrene is an important monomer used in the manufacture of manypolymers. Styrene is commonly produced by forming ethylbenzene, which isthen dehydrogenated to produce styrene. Ethylbenzene is typically formedby one or more aromatic conversion processes involving the alkylation ofbenzene.

Aromatic conversion processes, which are generally carried out utilizinga molecular sieve type catalyst, are well known in the chemicalprocessing industry. Such aromatic conversion processes include thealkylation of aromatic compounds such as benzene with ethylene toproduce alkyl aromatics, such as ethylbenzene. Other alkylationprocesses include the alkylation of toluene with methanol and/orformaldehyde to produce styrene and ethylbenzene. Unfortunately, thesealkylation processes have generally been characterized by low yields ofdesired products and low selectivity to styrene and ethylbenzene.

The molecular sieve catalysts that are suitable for use in thesealkylation reactions typically include zeolites. The most commerciallyavailable zeolites are prepared such that the zeolite crystal is greaterthan 1 μm.

In view of the above, it would be desirable to develop processes offorming styrene and/or ethylbenzene capable of increased yields andimproved selectivity.

SUMMARY

Embodiments of the present invention include a method of making analkylation catalyst by providing a nanosize zeolite and contacting itwith a solution to create a dispersion solution having dispersednanosize zeolite particles. The dispersion solution is contacted with asupport material to create a wetted support. The wetted support is driedto obtain a catalyst that includes a nanosize zeolite.

The nanosize zeolite can have a particle size of less than 1000 nm orless than 300 nm and can be formed from a faujasite, such as an X-typeor Y-type zeolite. The support material can be selected from the groupconsisting of silica, alumina, aluminosilica, titania, and zirconia andcombinations thereof. The catalyst can include a promoter selected fromthe group consisting of Ru, Rh, Ni, Co, Pd, Pt, Mn, Ti, Zr, V, Nb, K,Cs, Ga, P, B, Rb, Ag, Ge, Cu, Mg, and Na and combinations thereof.

An alternate embodiment of the present invention is a method of making acatalyst for styrene production by contacting a nanosize zeolite with asolution to create a dispersion solution having dispersed nanosizezeolite particles. A nanocarrier is added to the dispersion solutionthat is contacted with a support material to create a wetted support.The wetted support is then dried to obtain a catalyst comprising ananosize zeolite. The nanocarrier can be any material having anelectrostatic interaction with the zeolite material, or that includesmaterial that can attract nanoparticles with columbic interaction, suchas for example a silica oxide material or a boehmite alumina material.

A further embodiment of the present invention is a styrene productionprocess that includes contacting a carbon (C₁) source with toluene inthe presence of a catalyst disposed within a reactor to form a productstream comprising styrene. The catalyst includes a nanosize zeolite.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a flow chart for the production of styrene by thereaction of formaldehyde and toluene, wherein the formaldehyde is firstproduced in a separate reactor by either the dehydrogenation oroxidation of methanol and is then reacted with toluene to producestyrene.

FIG. 2 illustrates a flow chart for the production of styrene by thereaction of formaldehyde and toluene, wherein methanol and toluene arefed into a reactor, wherein the methanol is converted to formaldehydeand the formaldehyde is reacted with toluene to produce styrene.

FIG. 3 is a Transmission Electron Microscopy (TEM) image of anembodiment of the present invention that shows nanozeolites incorporatedin the pores of a silica substrate.

FIG. 4 is a TEM image of an embodiment of the present invention thatshows distribution of nanocarriers and nanozeolites incorporated in thepores of a silica substrate.

FIG. 5 is a TEM image of an embodiment of the present invention thatshows a nanozeolite incorporated silica sample after use as a catalystin an alkylation reaction of toluene and methanol.

DETAILED DESCRIPTION

A detailed description will now be provided. Each of the appended claimsdefines a separate invention, which for infringement purposes isrecognized as including equivalents to the various elements orlimitations specified in the claims. Depending on the context, allreferences below to the “invention” may in some cases refer to certainspecific embodiments only. In other cases it will be recognized thatreferences to the “invention” will refer to subject matter recited inone or more, but not necessarily all, of the claims. Each of theinventions will now be described in greater detail below, includingspecific embodiments, versions and examples, but the inventions are notlimited to these embodiments, versions or examples, which are includedto enable a person having ordinary skill in the art to make and use theinventions when the information in this patent is combined withavailable information and technology.

Various terms as used herein are shown below. To the extent a term usedin a claim is not defined below, it should be given the broadestdefinition skilled persons in the pertinent art have given that term asreflected in printed publications and issued patents at the time offiling. Further, unless otherwise specified, all compounds describedherein may be substituted or unsubstituted and the listing of compoundsincludes derivatives thereof.

Further, various ranges and/or numerical limitations may be expresslystated below. It should be recognized that unless stated otherwise, itis intended that endpoints are to be interchangeable. Further, anyranges include iterative ranges of like magnitude falling within theexpressly stated ranges or limitations.

Styrene production processes generally include reacting toluene withmethanol or methane/oxygen as co-feed. In practice, the methanol (CH₃OH)often dehydrogenates into side-products, resulting in lower than desiredtoluene conversion and/or lower than desired selectivity. As usedherein, the term “selectivity” refers to the percentage ofinput/reactant converted to a desired output/product. Such lowconversion/selectivity rates generally lead to processes that are noteconomical.

However, the processes described herein (and particularly the catalystsdescribed herein in combination with the described processes) arecapable of minimizing side product formation, thereby resulting inincreased conversion and/or selectivity.

In one or more embodiments, the styrene production processes includereacting toluene with a carbon source, which can be referred to as a C₁source (e.g., a carbon source capable of cross-coupling with toluene toform styrene, ethylbenzene or combinations thereof), in the presence ofa catalyst to produce a product stream including styrene andethylbenzene. For example, the C₁ source may include methanol,formaldehyde or a mixture thereof. Alternatively, the C₁ source includestoluene reacted with a C₁ source selected from one or more of thefollowing: formalin (37 wt. % to 50 wt. % H₂CO in a solution of waterand MeOH), trioxane (1,3,5-trioxane), methylformcel (55 wt. % H₂CO inmethanol), paraformaldehyde and methylal (dimethoxymethane). In anotherembodiment, the C₁ source is selected from methanol, formaldehyde,formalin, trioxane, methylformcel, paraformaldehyde, methylal,dimethylether, dimethoxyethane, and combinations thereof.

Formaldehyde can be produced by the oxidation or dehydrogenation ofmethanol, for example. In one embodiment, formaldehyde is produced bythe dehydrogenation of methanol to produce formaldehyde and hydrogengas. This reaction step generally produces a dry formaldehyde stream,thereby eliminating separation of formed water prior to the reaction ofthe formaldehyde with toluene. The dehydrogenation process is describedin the equation below:CH₃OH→CH₂O+H₂

Formaldehyde can also be produced by the oxidation of methanol toproduce formaldehyde and water. The oxidation of methanol is describedin the equation below:2CH₃OH+O₂→2CH₂O+2H₂O.

When utilizing a separate process to obtain formaldehyde, a separationunit may then be used to separate the formaldehyde from the hydrogen gasor water from the formaldehyde and unreacted methanol prior to reactingthe formaldehyde with toluene for the production of styrene. Suchseparation inhibits hydrogenation of the formaldehyde back to methanol.The formaldehyde can then be sent to a styrene reactor and the unreactedmethanol recycled, for example.

Although the equations illustrated above show a 1:1 molar ratio oftoluene and the C₁ source, such molar ratio is not limited within theembodiments herein and can vary depending on operating conditions andefficiency of the reaction system. For example, if excess toluene or C₁source is fed to the reaction zone, the unreacted portion can besubsequently separated and recycled back into the process. In oneembodiment the molar ratio of toluene:C₁ source can range from 100:1 to1:100. In alternate embodiments, the molar ratio of toluene:C₁ sourcecan range from 50:1 to 1:50, or from 20:1 to 1:20, or from 10:1 to 1:10,or from 5:1 to 1:5 or from 2:1 to 1:2, for example.

The styrene production process generally includes catalyst disposedwithin one or more reactors. The reactors may include fixed bedreactors, fluid bed reactors, entrained bed reactors or combinationsthereof, for example. Reactors capable of operation at the elevatedtemperature and pressure as described herein, and capable of enablingcontact of the reactants with the catalyst, can be considered within thescope of the present invention. Embodiments of the particular reactorsystem may be determined based on the particular design conditions andthroughput, as by one of ordinary skill in the art, and are not meant tobe limiting on the scope of the present invention.

In another aspect, the one or more reactors may include one or morecatalyst beds. When utilizing multiple beds, an inert material layer mayseparate each bed. The inert material may include any type of inertsubstance, such as quartz, for example. In one or more embodiments, thereactor includes from 1 to 10 catalyst beds, or from 2 to 8 catalystbeds, or from 2 to 6 catalyst beds, for example. The C₁ source andtoluene may be injected into a catalyst bed, an inert material layer orcombinations thereof, for example. Both the C₁ source and toluene may beinjected into a catalyst bed, optionally both the C₁ source and toluenemay be injected into an inert material layer. Alternatively, at least aportion of the C₁ source may be injected into a catalyst bed(s) and atleast a portion of the toluene feed is injected into an inert materiallayer(s). In yet another embodiment, the entire C₁ source may beinjected into a catalyst bed(s) and all of the toluene feed is injectedinto an inert material layer(s). Alternatively, at least a portion ofthe toluene feed may be injected into a catalyst bed(s) and at least aportion the C₁ source may be injected into an inert material layer(s).In yet another embodiment, all of the toluene feed may be injected intoa catalyst bed(s) and the entire C₁ source may be injected into an inertmaterial layer(s).

The operating conditions of the reactors will be system specific and canvary depending on the feedstream composition and the composition of theproduct streams. In one or more embodiments, the reactor(s) may operateat elevated temperatures and pressures, for example.

In one or more embodiments, the elevated temperature can range from 250°C. to 750° C., or from 300° C. to 500° C. or from 325° C. to 450° C.,for example. The pressure can range from 0.1 atm to 70 atm, or from 0.1atm to 35 atm, or from 1 atm to 5 atm, for example.

FIG. 1 illustrates a simplified flow chart of one embodiment of thestyrene production process described above wherein the C₁ source isformaldehyde. In this embodiment, a first reactor (2) is either adehydrogenation reactor or an oxidation reactor. First reactor (2) isdesigned to convert a first methanol feed (1) into formaldehyde. Theproduct stream (3) of the first reactor (2) may then be sent to anoptional gas separation unit (4) where the formaldehyde is separatedfrom any unreacted methanol (6) and unwanted byproducts (5). Anyunreacted methanol (6) can then be recycled back into the first reactor(2). The byproducts (5) are separated from the clean formaldehyde (7).

In one embodiment, the first reactor (2) is a dehydrogenation reactorthat produces formaldehyde and hydrogen and the gas separation unit (4)is a membrane capable of removing hydrogen from the product stream (3).

In an alternate embodiment, the first reactor (2) is an oxidativereactor that produces product stream (3) comprising formaldehyde andwater. The product stream (3) comprising formaldehyde and water can thenbe sent to the second reactor (9) without a gas separation unit (4).

The clean formaldehyde (7) is then reacted with a feed stream of toluene(8) in the second reactor (9) in the presence of a catalyst (not shown)disposed in the second reactor (9). The toluene and formaldehyde reactto produce styrene. The product (10) of the second reactor (9) may thenbe sent to an optional separation unit (11) where any unwantedbyproducts (15), such as water, can be separated from the styrene,unreacted formaldehyde (12) and unreacted toluene (13). Any unreactedformaldehyde (12) and unreacted toluene (13) can be recycled back intothe second reactor (9). A styrene product stream (14) can be removedfrom the separation unit (11) and subjected to further treatment orprocessing if desired.

FIG. 2 illustrates a simplified flow chart of another embodiment of thestyrene process discussed above wherein the C₁ source is methanol. Amethanol containing feed stream (21) is fed along with a feed stream oftoluene (22) to a reactor (23) having a catalyst (not shown) disposedtherein. The methanol reacts with the catalyst to produce a product (24)including styrene. The product (24) of the reactor (23) may then be sentto an optional separation unit (25) where any unwanted byproducts (26)can be separated from the styrene, unreacted methanol (27), unreactedformaldehyde (28) and unreacted toluene (29). Any unreacted methanol(27), unreacted formaldehyde (28) and unreacted toluene (29) can berecycled back into the reactor (23). A styrene product stream (30) canbe removed from the separation unit (25) and subjected to furthertreatment or processing if desired.

The catalyst utilized for the processes described herein generallyincludes a zeolitic material. As used herein, the term “zeoliticmaterial” refers to a molecular sieve containing an alumino silicatelattice. Zeolitic materials are well known in the art and possesswell-arranged pore systems with uniform pore sizes. However, thesematerials tend to possess either only micropores or only mesopores, inmost cases only micropores. Micropores are defined as pores having adiameter of less than about 2 nm. Mesopores are defined as pores havinga diameter ranging from about 2 nm to about 50 nm. Micropores generallylimit external molecules access to the catalyticly active sites insideof the micropores or slow down diffusion to the catalyticly activesites.

Embodiments of the present invention utilize a nanosize zeolite. As usedherein, the term “nanosize zeolite” refers to zeolitic materials havinga particle size smaller than 1000 nm (1 μm). For example, the particlesize may be less than 1000 nm, or less than 300 nm, or less 100 nm, orless than 50 nm, or less than 25 nm, for example. In one or moreembodiments, the particle size is from 1.0 nm to 1000 nm, or from 10 nmto 500 nm, or from 25 nm to 300 nm, or from 50 nm to 100 nm or from 50nm to 75 nm, for example. As used herein, the “particle size” refers toeither the size of each discrete crystal (i.e., crystal) of the zeoliticmaterial or the size of an agglomeration of particles (i.e.,crystallite) within the zeolitic material. The particles of nanosizezeolite may also be referred to as nanoparticles.

The zeolitic materials may include silicate-based zeolites, such asfaujasites and mordenites, for example. Silicate-based zeolites may beformed of alternating SiO₂ and MO_(x) tetrahedra, where M is an elementselected from the Groups 1 through 16 of the Periodic Table. Such formedzeolites may have 4, 6, 8, 10, or 12-membered oxygen ring channels, forexample. An example of a faujasite are X-type and Y-type zeolites. Thezeolitic material may have a Si/Al ratio of 1.0 or greater. In anembodiment the Si/Al ratio can range from 1.0 to 200. In an alternateembodiment the Si/Al ratio can range from 1.0 to 100. In an alternateembodiment the Si/Al ratio can range from 1.0 to 50. In an alternateembodiment the Si/Al ratio can range from 1.0 to 25.

Optional support materials may include silica, alumina, aluminosilica,titania, zirconia and combinations thereof, for example. An optionalsupport material can be a larger crystal size faujasite, such as aconventional sized zeolite, that can support a nanosize zeolite.

The catalyst generally includes from 1 wt. % to 99 wt. %, or from 3 wt.% to 90 wt. % or from 4 wt. % to 80 wt. % nanosize zeolite in the finalcatalyst, for example. In an embodiment the nanosize zeolite ranges from5 wt. % to 50 wt. %, optionally from 5 wt. % to 30 wt. %. In one or moreembodiments, the catalyst includes from 5 wt. % to 20 wt. %, or from 5wt. % to 15 wt. % or from 7 wt. % to 12 wt. % support material in thefinal catalyst, for example.

In one or more embodiments, the nanosize zeolite may have an increasedratio of surface area to volume compared to zeolitic materials that arenot nanosize, for example. For example the nanosize zeolite may have atleast 50% higher ratio of surface area to volume compared to zeoliticmaterials that are not nanosize, optionally at least 100% higher ratio,optionally at least two times higher ratio, optionally at least fivetimes higher ratio, optionally at least ten times higher ratio.

The nanosize zeolite may be supported, or added, by any method(s) knownto one skilled in the art. In an embodiment, these methods may includeincipient wetness impregnation. In an alternative embodiment, thenanosize zeolite can be admixed with a support material. In a furtherembodiment, the nanosize zeolite may be supported in-situ with thesupport material or extruded. In an additional embodiment, the nanosizezeolite may be supported by spray-coating it onto a support material. Itis further contemplated that such support processes may include layeringthe nanosize zeolite onto the support material, such as the supportmaterials described below or optionally polymer spheres, such aspolystyrene spheres, for example. It is even further contemplated thatsuch support processes may include the utilization of zeoliticmembranes, for example.

In one specific embodiment, the nanosize zeolite is supported by asupport material and the nanosize zeolite is added to the supportmaterial via incipient wetness impregnation. In an embodiment, thisprocess includes dispersing a nanosize zeolite in a diluent, such asnon-limiting examples of methanol or toluene, to yield individuallydispersed crystals, or individually dispersed nanoparticles. A supportmaterial may then be added to the solution and mixed until dry. In anembodiment, the dispersing of the nanoparticles of the nanosize zeolitein a solution is naturally dispersed or can be aided by agitation. Anysuitable means of agitation can be used. In a specific embodiment, theagitation includes sonication.

In the incipient wetness impregnation method, the nanoparticles can havean affinity for one another and can form conglomerations inside thepores of the substrate. These conglomerations may become bound insidethe support material, causing the nanosize zeolite to be supported bythe support material. But conglomerations of the nanoparticles withinthe pores of the substrate are not necessary for the nanoparticles to besupported by the substrate.

In another embodiment, the nanoparticles may be added to the supportaided by the use of carriers. In an embodiment, this process includesdispersing a nanosize zeolite in a diluent, such as methanol or toluene,to yield individually dispersed crystals, or individually dispersednanoparticles. A support material may then be added to the solution andmixed. A carrier may be added to the solution at any point during themixing. In an embodiment, the carrier is added to the diluent before thenanosize zeolite is added. In another embodiment, the carrier is addedto the diluent after the nanosize zeolite is added and before thesupport material is added. In a further embodiment, the carrier is addedafter the nanosize zeolite and support material are added to thediluent. In an aspect, the zeolitic material, the catalytically activepromoter, the support material or combinations thereof may optionally becontacted with a carrier prior to contact of the zeolitic material withthe catalytically active promoter. This can be done by having an ionexchange, or other process of addition, performed after a supportingstep. The carrier may be adapted to aid in the incorporation of thecatalytically active promoter into the zeolitic material, for example.In one or more embodiments, the carrier is a nano-sized carrier, ornanocarrier (with the nano-sized carrier defined as for nanosizezeolites, as described above). In an embodiment, the carrier may includealuminum. In a more specific embodiment, the aluminum-containing carrierincludes boehmite alumina. In an embodiment, the nanocarrier comprisesmaterial that can attract nanoparticles with columbic interaction.

In one embodiment, the nanosize zeolite is formed by utilizing a carrierto transport the nanosize zeolite into pores of the support material. Inan embodiment, the carrier includes boehmite alumina. The carrier may bethen be added to a solution containing toluene or methanol. Boehmitealumina is a nano-sized crystallite having particle sizes from about 10to 15 nm. These nanoparticles have a high surface charge that can adheresmall particles, such as nano-zeolites, which can be beneficial intransporting the zeolites into the pores of the silica support material.The formed zeolite may then be dried and subjected to thermal treatment.During thermal treatment, the silica and alumina can bond and hold thezeolite in a cage-like assembly for catalytic activity. In a furtherembodiment, the carrier may be mixed with a solvent prior to contactwith the nanosize zeolite.

In an embodiment, the nanosize zeolite is supported by physical additionof the nanosize zeolite with the zeolitic support. In anotherembodiment, the nanosize zeolite is supported by forming an extrudablematerial utilizing a support material in combination with the nanosizezeolite to form extrudates and/or tablets.

The nanosize zeolite may be chemically modified so that it will graftonto a support. In an embodiment, the nanosize zeolite is supported bysurface modification of the nanosize zeolite followed by grafting themodified nanosize zeolite onto a support. In an embodiment, the supportis selected from the group of silica, alumina, a monolith structure andcombinations thereof. In another embodiment, the nanosize zeolite issupported by a process including: surface modifying the nanosizezeolites using a grafting molecule such as a silane (silica havingfunctional groups) to yield a surface modified nanosize zeolite, whereinthe surface modified nanosize zeolite has terminal reactive functionalgroups which can help to graft the nanosize zeolite onto a support.

In an embodiment, the nanosize zeolite is deposited on a support by anysuitable means, such as by non-limiting example one selected from thegroup of dip-coating, spray-coating, and wash-coating and anycombinations thereof. The nanosize zeolite may be wash-coated on amonolith or an inert structured support for example.

The nanosize zeolite may be supported in situ with the support material.In an embodiment, the nanosize zeolite particles are created in situwith the support material. In another embodiment, the nanosize zeoliteparticles are simultaneously created and supported in situ with thesupport material.

The catalysts described herein may increase the effective diffusivity ofthe reactants, thereby increasing reactant conversion to desiredproducts. Furthermore, the catalysts may result in processes exhibitingimproved product selectivity over processes utilizing conventionalzeolitic materials. In addition, activity of such processes may beincreased due to an increase of accessibility of active sites, whichthereby increases the effective number of active sites per weight ofcatalyst over larger non-nanosize zeolites.

Optionally, a catalytically active element, such as a catalyticallyactive metal, may be incorporated into the nanosize zeolite by, forexample, ion-exchange or impregnation of the zeolitic material, or byincorporating the active element in the synthesis materials from whichthe zeolitic material is prepared. As described herein, the term“incorporated into the zeolitic material” refers to incorporation intothe framework of the zeolitic material, incorporation into channels ofthe zeolitic material (i.e., occluded) or combinations thereof.

The catalytically active element can be in a metallic form, combinedwith oxygen (e.g., metal oxide) or include derivatives of the compoundsdescribed below, for example. Suitable catalytically active metalsdepend upon the particular process in which the catalyst is intended tobe used and generally include, but are not limited to, alkali metals(e.g., Li, Na, K, Rb, Cs, Fr), rare earth “lanthanide” metals (e.g., La,Ce, Pr), Group IVB metals (e.g., Ti, Zr, Hf), Group VB metals (e.g., V,Nb, Ta), Group VIB metals (e.g., Cr, Mo, W), Group IB metals (e.g., Cu,Ag, Au), Group VIIIB metals (e.g., Pd, Pt, Ir, Co, Ni, Rh, Os, Fe, Ru),Group IIIA metals (e.g., Ga), Group IVA metals (e.g., Ge) andcombinations thereof, for example. Alternatively (or in combination withthe previously discussed metals), the catalytically active element mayinclude a Group IIIA compound (e.g., B), a Group VA compound (e.g., P)or combinations thereof, for example. In one or more embodiments, thecatalytically active element is selected from Cs, Na, B, Ga andcombinations thereof.

In one or more embodiments, the nanosize zeolite may include less than15 wt. % sodium of the total weight of active catalyst, optionally lessthan 10 wt. % sodium, optionally less than 7 wt. % sodium. In one ormore embodiments, the nanosize zeolite may include less than 25 wt. %aluminum of the total weight of active catalyst, optionally less than 20wt. % aluminum, optionally less than 14 wt. % aluminum. In one or moreembodiments, the nanosize zeolite may include at least 10 wt. % cesiumof the total weight of active catalyst, optionally at least 20 wt. %cesium, optionally at least 25 wt. % cesium. In one or more embodiments,the nanosize zeolite may include less than 30 wt. % silicon of the totalweight of active catalyst, optionally less than 25 wt. % silicon,optionally less than 18 wt. % silicon. In one or more embodiments, thenanosize zeolite may include less than 10 wt. % boron of the totalweight of active catalyst, optionally less than 5 wt. % boron,optionally less than 3 wt. % boron. The balance of the nanosize zeolitewill generally be formed of oxygen. If other elements are included inthe material, then these amounts may be altered.

Increased side chain alkylation selectivity towards desired products maybe achieved by treating the catalyst with chemical compounds to inhibitselect basic sites. Such improvement may be accomplished by the additionof a second element. The second element can be one of those mentionedabove. For example, in one or more embodiments, the second element mayinclude boron.

The processes described herein may exhibit a toluene conversion of atleast 0.01 mol. %, or from 0.05 mol. % to 80 mol. %, or from 2 mol. % to25 mol. % or from 5 mol. % to 25 mol. % for example.

The process may exhibit a selectivity to styrene of at least 1 mol. %,or from 1 mol. % to 99 mol. %, or at least 30 mol. % or from 65 mol % to99 mol %, for example.

-   -   The process may exhibit a selectivity to ethylbenzene of at        least 5 mol. %, or from 5 mol. % to 99 mol. %, or at least 10        mol. % or from 8 mol % to 99 mol %, for example.

EXAMPLES Example 1

A supported nanosize zeolite material was prepared according to theincipient wetness impregnation method. In this method, 18 mg ofnanozeolite (Cs/Y) having a size of about 60 nm were dispersed intoluene and then loaded on to 570 mg of silica support.

The Transmission Electron Microscopy (TEM) image in FIG. 3 shows thatnanozeolites (Cs/Y), indicated by circles, are incorporated in the poresof the silica substrate and that they are well distributed.

Example 2

A supported nanosize zeolite material was prepared by utilizingnanocarriers. In this method, 2.18 g of nanozeolite (Cs/Y) having anaverage size as determined by TEM of about 60 nm were dispersed in 250ml of toluene using sonication cycles creating a dispersion solution.Each sonication cycle was comprised of a five minute period at 450 wattsand 21 amplitude level, followed by five minutes of inactivity to allowthe solution to cool. This cycle was repeated three times, for a totalof three cycles.

0.2 g of Catapal A alumina was added to the dispersion solution. CatapalA is a boehmite alumina, which is a nano-sized crystallite having sizesof about 10 to 15 nm. This boehmite alumina has a high surface chargethat can adhere the small particles of the nanozeolites. The Catapal Ais used as the nanocarrier. The mixture was then sonicated for fivecycles.

10.09 g of silica having an average pore diameter of about 379 nm sizeas determined by TEM, a pore volume of 0.78 cc/g, and bulk density of0.49 cc/g was then placed in an ion exchange column having an interiordiameter of 1 inch. The dispersion solution was then added to the 10.09g of silica in the ion exchange column. After the silica substrate wascompletely wet, the excess liquid was drained out and then left in ahood to air dry, followed by drying in a vented drying oven at 70° C.for 1 hr. This was repeated 19 times until the dispersion liquid wasconsumed.

The samples for TEM analysis were prepared by embedding the sample in anepoxy resin and curing the resin. The cured resin is then microtomed toultra thin sections containing the cross-sections of the nanozeolitesincorporated within the silica. The microtomed sections are placed on tothe carbon film coated copper grid for TEM investigation.

The image in FIG. 4 shows distribution of nanocarriers(Catapal-A-alumina) as indicated by the larger dashed circle, along withthe nanozeolites (Cs/Y), as indicated by the smaller dashed oval,incorporated in the pores of the silica substrate.

The catalyst containing nanozeolites incorporated along with nanocarrierCatapal-A-alumina on the silica substrate was then subjected to a benchscale reaction of toluene and methanol (1:1 molar ratio; 22 cc/hr) in a0.75-inch diameter stainless steel tube for a period of 5 hrs underalkylation conditions of 425° C., 3.5 psig, and a contact time of from 2to 3 seconds. After the reaction the catalyst was analyzed by TEM toidentify the presence of nanozeolites. FIG. 5 is a TEM analysis of thenanozeolite incorporated silica sample after the ATM reaction, and showsthat nanozeolites have adhered to the walls of the silica support anddid not get washed out under the reaction conditions. The nanocarriers(Catapal-A-alumina) as indicated by the larger dashed circles, alongwith the nanozeolites (Cs/Y), as indicated by the smaller dashed ovals,were still found incorporated in the pores of the silica substrate.

As used herein, the term “activity” refers to the weight of productproduced per weight of the catalyst used in a process at a standard setof conditions per unit time.

The term “conversion” refers to the percentage of reactant (e.g.toluene) that undergoes a chemical reaction.X _(Tol)=conversion of toluene (mol %)=(Tol_(in)=Tol_(out))/Tol_(in)X _(MeOH)=conversion of methanol to styrene+ethylbenzene (mol %)

The term “molecular sieve” refers to a material having a fixed,open-network structure, usually crystalline, that may be used toseparate hydrocarbons or other mixtures by selective occlusion of one ormore of the constituents, or may be used as a catalyst in a catalyticconversion process.

The term “monolith” as used herein refers to a honeycombed substrate,such as a ceramic or metal honeycombed substrate, that can contain acatalyst element.

Use of the term “optionally” with respect to any element of a claim isintended to mean that the subject element is required, or alternatively,is not required. Both alternatives are intended to be within the scopeof the claim. Use of broader terms such as comprises, includes, having,etc. should be understood to provide support for narrower terms such asconsisting of, consisting essentially of, comprised substantially of,etc.

The term “selectivity” refers to the relative activity of a catalyst inreference to a particular compound in a mixture. Selectivity isquantified as the proportion of a particular product relative to allother products.S _(Sty)=selectivity of toluene to styrene (mol%)=Sty_(out)/Tol_(converted)S _(Bz)=selectivity of toluene to benzene (mol%)=Benzene_(out)/Tol_(converted)S _(EB)=selectivity of toluene to ethylbenzene (mol %)=EB_(out)/Tol_(converted)S _(Xyl)=selectivity of toluene to xylenes (mol%)=Xylenes_(out)/Tol_(converted)S _(Sty+EB)(MeOH)=selectivity of methanol to styrene+ethylbenzene (mol%)=(Sty_(out) +EB _(out))/MeOH_(converted)

The term “zeolite” refers to a molecular sieve containing analuminosilicate lattice, usually in association with some aluminum,boron, gallium, iron, and/or titanium, for example. In the followingdiscussion and throughout this disclosure, the terms molecular sieve andzeolite will be used more or less interchangeably. One skilled in theart will recognize that the teachings relating to zeolites are alsoapplicable to the more general class of materials called molecularsieves.

Depending on the context, all references herein to the “invention” mayin some cases refer to certain specific embodiments only. In other casesit may refer to subject matter recited in one or more, but notnecessarily all, of the claims. While the foregoing is directed toembodiments, versions and examples of the present invention, which areincluded to enable a person of ordinary skill in the art to make and usethe inventions when the information in this patent is combined withavailable information and technology, the inventions are not limited toonly these particular embodiments, versions and examples. Other andfurther embodiments, versions and examples of the invention may bedevised without departing from the basic scope thereof and the scopethereof is determined by the claims that follow.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A styrene production process comprising:providing a C₁ source, wherein the C₁ source is selected from methanol,formaldehyde, formalin, trioxane, methylformcel, paraformaldehyde andmethylal and combinations thereof; contacting the C₁ source with toluenein the presence of a catalyst disposed within a reactor to form aproduct stream comprising styrene, wherein the catalyst comprisesnanosize zeolite particles, wherein the nanosize zeolite particlescomprise a Y-type zeolite, and wherein the catalyst is produced by:incorporating one or more catalytically active promoters into thenanosize zeolite particles, wherein the one or more catalytically activepromoters are selected from the group consisting of Cs, Ga, B, Na, andcombinations thereof; contacting and dispersing the nanosize zeoliteparticles with a solution to create a dispersion solution comprisingdispersed nanosize zeolite particles; adding a nanocarrier to thedispersion solution prior to contacting the dispersion solution with asupport material, wherein the nanocarrier comprises a silica oxidematerial or an aluminum-containing material; contacting the supportmaterial with the dispersion solution to create a wetted support and tothereby incorporate the nanosize zeolite particles into the supportmaterial; and drying the wetted support to obtain a catalyst; andrecovering the product stream from the reactor.
 2. The process of claim1, further comprising contacting the nanosize zeolite particles with asilane resulting in a modified nanosize zeolite; grafting the modifiednanosize zeolite onto a support; and calcining the modified nanosizezeolite grafted onto the support, resulting in a catalyst comprisingnanosize zeolite particles.
 3. The process of claim 1, wherein thecatalyst is produced by physically combining nanosize zeolite particleswith a support to form extrudates.
 4. The process of claim 1, whereinthe catalyst is produced by simultaneously creating and supportingnanosize zeolite particles in situ with the support material.
 5. Theprocess of claim 1, further comprising converting a C₁ source to form anintermediate product selected from formaldehyde, hydrogen, water,methanol and combinations thereof.
 6. The process of claim 1, whereinthe C₁ source comprises a mixture of methanol and formaldehyde.
 7. Theprocess of claim 1, wherein the nanosize zeolite particles have aparticle size of less than about 1000 nm.
 8. The process of claim 1,wherein the nanocarrier comprises a silica oxide material or an aluminumcontaining material.
 9. The process of claim 1, wherein the nanocarriercomprises boehmite alumina.